Solved >10.13.6 High Sierra update won’t apply

Hello, I recently reinstalled macOS and am trying to update High Sierra with the most recent security update. When my computer restarts, it attempts to boot to the installer volume, which boots to a screen with the default desktop and the large High Sierra logo that is used in the actual OS installer, but not updates. The computer stays at this screen for a couple seconds and reboots. If I manually select to boot to the normal volume, the security update needs to be downloaded again, and this repeats. My boot drive is formatted as HFS+ not APFS. Any ideas?
Thanks in advance!

I think the “Install” volume contains the original installer data because I erased, not deleted, my previous APFS container, therefore it may be using the Preboot from the container. I’ll update if I learn more.

Nope. I believe it has to do with bypassing APFS at the install, because the “Install macOS” option in clover appears and automatically boots when it should, but shows the installer from the original install, and then crashes. Any ideas?

So you have to reformat in APFS? I'm having same issue. I don't recall reformatting drive to APFS. I'll restore from TM after reformatting. Strange, as I don't recall setting my FS to APFS when i installed. I have really old setup upgrading from an old ML setup )